U.S. patent number 7,076,123 [Application Number 10/209,337] was granted by the patent office on 2006-07-11 for optoelectronic package having a transmission line between electrical components and optical components.
This patent grant is currently assigned to Intel Corporation. Invention is credited to Marc Epitaux, Peter E. Kirkpatrick, Rickie C. Lake, Craig Schulz, Jean-Marc Verdiell.
United States Patent |
7,076,123 |
Kirkpatrick , et
al. |
July 11, 2006 |
Optoelectronic package having a transmission line between
electrical components and optical components
Abstract
Described herein is a hermetic fiber optic package that may have
a wide bandwidth radio frequency (e.g., between 9 kHz and 300 GHz)
interface and a multilayer substrate provides a platform to
integrated various components such as, for example, integrated
circuits having electronic components, optoelectronic components,
or optics. In one embodiment, the substrate has a wide bandwidth
surface mountable interface that may be a single ended or a
differential that allows for an electrical signal to pass from the
exterior of the package to the interior. The interior of the
package contains a "riser" that is used to bring an electrical
signal from the plane of the substrate to the plane close to the
optical axis. This riser includes a transmission line to achieve
the change in height. The transmission line can be single ended or
differential. Also within the package is a "submount" upon which
electrical/optical/electro-optic components can be integrated.
Inventors: |
Kirkpatrick; Peter E.
(Berkeley, CA), Verdiell; Jean-Marc (Palo Alto, CA),
Schulz; Craig (Fremont, CA), Epitaux; Marc (Sunnyvale,
CA), Lake; Rickie C. (Sunnyvale, CA) |
Assignee: |
Intel Corporation (Santa Clara,
CA)
|
Family
ID: |
31187025 |
Appl.
No.: |
10/209,337 |
Filed: |
July 30, 2002 |
Prior Publication Data
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|
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Document
Identifier |
Publication Date |
|
US 20040022476 A1 |
Feb 5, 2004 |
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Current U.S.
Class: |
385/14 |
Current CPC
Class: |
G02B
6/4201 (20130101) |
Current International
Class: |
G02B
6/12 (20060101) |
Field of
Search: |
;385/14,92,93,16,88,75,8-9 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Font; Frank G.
Assistant Examiner: Wong; Eric
Attorney, Agent or Firm: Boyd; Rick D.
Claims
What is claimed is:
1. An apparatus comprising: an electrical component; a riser having
a transmission line patterned thereon, the transmission line
coupled with the electrical component, the transmission line
traversing from at least a first plane to at least a second plane;
and an optoelectronic component disposed atop the riser, the
optoelectronic component coupled with the transmission line to
communicate signals with the electrical component.
2. The apparatus of claim 1 wherein the interface receives
high-frequency signals between 9 kHz and 300 GHz.
3. The apparatus of claim 1 wherein the riser comprises a thick
film riser.
4. The apparatus of claim 1 wherein the transmission line comprises
one or more metal lines printed on the riser.
5. The apparatus of claim 1 wherein the transmission line comprises
a single-ended transmission line.
6. The apparatus of claim 1 wherein the transmission line comprises
a differential transmission line.
7. The apparatus of claim 1 wherein the optoelectronic component
and the riser are disposed within a hermetically sealed
package.
8. The apparatus of claim 1 wherein the optoelectronic component
comprises one or more of: a laser diode, a photodetector, and an
amplifier.
9. An apparatus comprising: a first level having an interface at
which one or more electrical signals are at least one of received
and transmitted; a second level having of at least one of an
electronic, optical, and optoelectronic component; and a riser
disposed between the first level and the second level, the riser
having a transmission line patterned thereon providing an
electrical connection between the interface on the first level and
the at least one of an electronic, optical, and optoelectronic
component on the second level.
10. The apparatus of claim 9 wherein the first level is
substantially parallel to the second level.
11. The apparatus of claim 9 wherein the riser comprises a thick
film riser.
12. The apparatus of claim 9 wherein the riser comprises a ceramic
riser.
13. The apparatus of claim 9 wherein the transmission line
comprises one or more metal lines printed on the riser.
14. The apparatus of claim 9 wherein the transmission line
comprises a single-ended transmission line.
15. The apparatus of claim 9 wherein the transmission line
comprises a differential transmission line.
16. The apparatus of claim 9 further comprising a second
transmission line coupled between the first level and the second
level.
17. The apparatus of claim 9 wherein the first level, the second
level, and the riser are disposed within a hermetically sealed
package.
18. The apparatus of claim 9 wherein the optical component
comprises one or more of: a laser diode, a photodetector, and an
amplifier.
19. An apparatus comprising: one or more electrical components on a
first plane; one or more optical components on a second plane; a
riser disposed between the electrical components and the optical
components; and a transmission line printed on the riser providing
a connection between the electrical components of the optical
components.
20. The apparatus of claim 19 wherein the first plane is
substantially parallel to the second plane.
21. The apparatus of claim 19 wherein the electrical components,
the optical components, the riser, and the transmission line for
providing an electrical connection between the electrical
components and the optical components are disposed within a
hermetically sealed package.
22. The apparatus of claim 19 wherein the one or more electrical
components comprise a die having an integrated circuit.
23. The apparatus of claim 19 wherein the one or more optical
components comprise one or more of: a laser diode, a photodetector,
and an amplifier.
24. An apparatus comprising: a substrate having a plurality of lead
pins to provide a high frequency interface; a riser disposed atop
the substrate; and one or more optical components disposed atop the
riser, the one or more optical components coupled with the
electrical interface by at least a transmission line patterned on
the riser.
25. The apparatus of claim 24 further comprising a cap and a seal
ring attached to the substrate to provide a hermetically sealed
environment for the riser, the one or more optical components and
the transmission line.
26. The apparatus of claim 24 further comprising the one or more
electrical components disposed atop the substrate that comprise a
die having an integrated circuit.
27. A system comprising: a transmitting device having one or more
electrical components on a first plane, one or more optical
components on a second plane to transmit optical signals, a riser
disposed between the electrical components and the optical
components; an optical communications medium to carry signals
transmitted by the optical component of the transmitting device; a
receiving device having one or more electrical components on a
first plane, one or more optical components on a second plane to
receive optical signals, a riser disposed between the electrical
components and the optical components; and the riser of at least
one of the transmitting device or the receiving device having a
transmission line patterned thereon providing an electrical
connection between the first plane and the second plane of the at
least one of the transmitting device or the receiving device.
28. The system of claim 27 wherein the transmitting device is a
processor and the receiving device is a memory.
29. The system of claim 27 wherein the transmitting device is a
memory and the receiving device is a processor.
30. A system comprising: a transmitting device having one or more
electrical components on a first plane, one or more optical
components on a second plane to transmit optical signals to a
remote device, and a riser disposed between the electrical
components and the optical components; an optical communications
medium to carry signals transmitted by the optical component of the
transmitting device; a receiving device having one or more
electrical components on a first plane, one or more optical
components on a second plane to receive optical signals from the
remote device, and a riser disposed between the electrical
components and the optical components; and the riser of at least
one of the transmitting device or the receiving device having a
transmission line patterned thereon providing an electrical
connection between the first plane and the second plane of the at
least one of the transmitting device or the receiving device.
31. The system of claim 30 further comprising a bus coupled with
the transmitting device and with the receiving device, the bus to
provide a communications path between the transmitting device and a
processor and between the processor and the receiving device.
32. The apparatus of claim 30 wherein the one or more electrical
components comprise a die having an integrated circuit.
33. The apparatus of claim 5 wherein the single-ended transmission
line comprises a first ground line, signal line and a second ground
line.
34. The apparatus of claim 1 further comprising an interface having
a plurality of pins to receive signals from an external source, the
electrical component being coupled with the interface to operate on
electrical signals.
35. The apparatus of claim 34 wherein the electrical component is
disposed upon the first plane.
36. The apparatus of claim 34 wherein the electrical component is
disposed upon the second plane.
Description
TECHNICAL FIELD
The invention relates to optoelectronic packaging. More
specifically, the invention relates to an optoelectronic component
package having a transmission line between a high frequency
interface on a first plane and optical components on a second plane
in the component package.
BACKGROUND
As optical components have become increasingly integrated with
electronic components, packages for optoelectronic devices have
been developed. Individually, optical component packages and
electronic component packages have been designed to solve different
packaging problems. For example, optical components must be
carefully aligned and the alignment must be maintained for proper
functionality. Electronic components often require heat dissipation
elements to maintain the electronic device in a predetermined
operating temperature range.
In order to provide an interface between optical components and
electronic components to utilize the bandwidth provided by fiber
optics, it is necessary to provide devices which can perform
optical to electric, as well as electrical to optical conversion
and to pass signals between the electronic and optical domains.
Current packages typically have a coaxial radio frequency (RF)
interface or ceramic leaded interface. An alternative package is
the miniature dual in-line (MINI-DIL) package, which is a ceramic
can with ceramic walls and vertical leads.
Devices such as the butterfly package as well as the MINI-DIL
package are configured according to a can shape that have various
sidewalls. As a result, these devices are not capable of providing
a planar platform for optical components, including optical
transducers, transponders or the like. Moreover, the configuration
of such devices does not enable product fabrication utilizing such
techniques as machine vision.
FIG. 1 illustrates a butterfly/can package known in the art. When
configured as a transmitter, the butterfly/can package of FIG. 1
includes components to convert electrical signals into optical
signals and to transmit the optical signals. Another package that
can be used to encapsulate electrical and optical components is the
MINI-DIL package, which is illustrated in FIG. 2.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is illustrated by way of example, and not by way of
limitation, in the figures of the accompanying drawings in which
like reference numerals refer to similar elements.
FIG. 1 illustrates a butterfly/can package known in the art.
FIG. 2 illustrates a MINI-DIL package known in the art.
FIG. 3 illustrates one embodiment of an optical package having a
backside recessed connection.
FIG. 4 illustrates a top side view of one embodiment of the optical
package of FIG. 3.
FIG. 5 illustrates one embodiment of a multilayer substrate of the
package of FIGS. 3 and 4.
FIG. 6A illustrates one embodiment of a first ceramic layer of the
multilayer substrate of FIG. 5.
FIG. 6B further illustrates one embodiment of a layer of FIG.
5.
FIG. 6C illustrates one embodiment of a DC signal layer of the
multi-level substrate.
FIG. 6D illustrates one embodiment of a substrate top surface metal
layer.
FIG. 7 illustrates one embodiment of a transmitter in a package
having a vertical transmission line.
FIG. 8 illustrates one embodiment of an optical electronic
system.
FIG. 9 is a block diagram of one embodiment of an electronic
system.
DETAILED DESCRIPTION
Optical component packages having a transmission line to couple
optical components to electrical components are described.
In the following description, for purposes of explanation, numerous
specific details are set forth in order to provide a thorough
understanding of the invention. It will be apparent, however, to
one skilled in the art that the invention can be practiced without
some of these specific details. In other instances, structures and
devices are shown in block diagram form in order to avoid obscuring
the invention.
Overview
Described herein is a hermetic optoelectronic package that may have
a wide bandwidth (e.g., >15 GHz) radio frequency (RF) interface.
In one embodiment, a multilayer cofired ceramic (e.g.,
Alumina/Aluminum Nitride) substrate provides a platform to
integrate various components such as, for example, integrated
circuits having electronic components, optoelectronic components
(e.g., laser diodes, photodetectors), or optical components (e.g.,
isolators, fiber optic couplers, fibers, lenses). In one
embodiment, the substrate has an interface that allows for an
electrical signal to pass from the exterior of the package to the
interior. Note that in different embodiments, signals can pass both
directions, e.g., in a transmitter, the electrical signal passes
from the exterior to the interior, and in a receiver, the
electrical signal passes from the interior to the exterior. The
substrate can have a seal ring attached that provides for a
hermetic seal to a cap/lid through soldering or laser welding.
Atop the substrate is a "riser" that is used to bring an electrical
signal from the plane of the substrate to the plane close to the
optical axis of the package (i.e., the height at which light is
emitted by a laser diode or received by a photodetector). This
riser includes a transmission line to transmit signals from the
plane of the electrical signal to the optical components. The
transmission line can be single ended or differential. Also within
the package is a "submount" upon which
electrical/optical/electro-optic components can be integrated, for
example, laser diodes, monitor photodiodes, photodetectors, driver
amplifiers, transimedance amplifiers, capacitors, inductors,
thermistors. Patterning on the submount is used to route the
various electrical signals including transmission lines to bring
the electrical signal from the riser to the various components.
Package Configuration
FIG. 3 illustrates one embodiment of an optical package having a
backside recessed connection. Lead frame 400 is coupled to recessed
portions of optical package substrate 300. Backside surface of the
optical package includes recessed portions, which enable coupling
of leads 410, 420 and 430 to reduce the air gap between the lead
frame and a printed circuit board (PCB) or other component within
the package.
In one embodiment, the optical package connection includes a
recessed, intermediate layer for attaching leads 410, 420 and 430,
which couples the package to a printed circuit board (PCB) for
receiving electrical signals. The recessed configuration of the
package increases the space available for mounting optoelectronic
components to a top surface of substrate 300. In addition, the
recessed configuration provides a flat surface on a backside of the
package, which improves thermal dissipation. Moreover, the recessed
package configuration increases available system space by
eliminating coaxial connections for receiving or transmitting
signals.
FIG. 4 illustrates a top side view of one embodiment of the optical
package of FIG. 3. Substrate 300 includes the recessed portions on
an end opposed to the optical fiber (the opposed end). Along a top
surface of the optical package, cap 210 is coupled to this top
surface in order to encapsulate optical and/or electrical
components.
Internal Configuration
FIG. 5 illustrates one embodiment of a multilayer substrate of the
package of FIGS. 3 and 4. In one embodiment, the multilayer
substrate includes layer 320, layer 340 and layer 360; however, a
different number of layers can be used. In one embodiment, three
ceramic layers are coupled together utilizing one or more vias 308.
In one embodiment, the multilayer substrate 300 is a cofired,
multilayer ceramic substrate.
In one embodiment, multilayer substrate 300 includes riser 380, as
well as submount 390. Riser 380 can be, for example, a thick film
riser and submount 390 can be a thin film submount. In one
embodiment, a riser metal layer 385 is provided between riser 380
and submount 390. In addition, a submount metal layer 395 is formed
on a top surface of submount 390. Once formed, a patterned
transmission line 397 is formed to provide a RF signal path to the
components that reside on a top surface of submount 390. In one
embodiment, a vertical transmission line provides an
interconnection between the electronic components on one plane with
optical components on a second plane. In one embodiment, the
transmission line is out of the plane of the submount
(perpendicular in this case where it is vertical with respect to
the submount (e.g., 45 degrees)). In this case, the transmission
line can be a truly coplanar line (GSG or GSSG), with no separate
ground. While specific layers and/or materials have bee used with
respect to FIG. 5 and other descriptions, other materials and/or a
different number of layers can be used.
A vertical transmission line provides several advantages. The
vertical transmission line requires less space within the package
as vias to accomplish the same result. In one embodiment, the
vertical transmission line is printed on a vertical side of thick
film riser 380 using a metal printing technique. Because vias
through relatively thick layers can have an inconsistent thickness,
the printed vertical transmission line can provide improved
bandwidth.
FIG. 6A illustrates one embodiment of a first layer of the
multilayer substrate of FIG. 5. In one embodiment, the layer of
FIG. 6A includes a bottom surface 310, which is metalized ceramic
in order to enable RF shielding as well as contact to a heat sink.
Adjacent to substrate metalized layer 310, the recessed portions
302, 304 and 306 of the substrate enable coupling of leads 410, 420
and 430. Although the layer is illustrated with opposed recessed
portions 302 and 304 and adjacent portion 306, different recessed
portions of the layer may be made.
FIG. 6B further illustrates one embodiment of a layer substrate of
FIG. 5. Layer 330 is metalized to provide an RF signal path from
leads 430 to an interior of the substrate. In one embodiment, layer
330 includes a plurality of pads (332, 334 and 336) which are
utilized to couple to leads 410 and 420. In addition, layer 320
includes a plurality of vias in order to couple the RF signal path
layer 330 to the metalized substrate layer 310.
FIG. 6C illustrates one embodiment of a direct current (DC) signal
layer of the multi-level substrate. In one embodiment, the layer of
FIG. 6C is fabricated to form DC signal path layer 350, which
provides DC signal routing from bonding pads 342 and 344 to various
leads 410 and 420. Wire bonds 346 couple leads 410 to bond pad 342.
Likewise, bond pad 344 is coupled to leads 420 by wire bonds 348.
In one embodiment, the layer of FIG. 6C is fabricated to form DC
signal path layer 350, which provides DC signal routing from
bonding pads 372 and 374 to various leads 410 and 420. Printed
traces 356 and 358 and vias in layers 340 and 360 couple leads 410
and 420 to bond pads 372 and 374.
In one embodiment, layer 320 is fabricated to form the metalized
layer 310 and RF signal path layer 330. Likewise, a top surface of
layer 340 is fabricated to form the DC signal path layer 350 to
leads 410, 420 and 430. In addition, a top surface of layer 360 is
fabricated to form a top surface metal layer 370. In one
embodiment, once each of the layers are metalized, the ceramic
layers are cofired together to form the multilayer ceramic
substrate 300.
FIG. 6D illustrates one embodiment of a substrate top surface metal
layer. Substrate top surface metal layer 370 enables formation of
optoelectronic components onto a top surface of the substrate 300.
The transmission line, patterned onto the riser, as well as a
transmission line, patterned onto a metal layer 395 of submount
390, provide a signal path from the RF signal pads 376 to the
optical electrical components mounted on top of the submount layer
395.
In one embodiment, the vertical transmission line is a metal
pattern applied to the thick film riser. The vertical transmission
line can be a single ended or differential transmission line. While
only one vertical transmission line is described with respect to
FIG. 6D, any number of vertical transmission lines can be
provided.
FIG. 7 illustrates one embodiment of a transmitter in a package
having a vertical transmission line. In one embodiment, the
transmitter package includes lid cap 210, which is hermetically
sealed to the top surface of substrate 300. Seal ring 570 provides
a hermetic seal between substrate 200 and lid cap 210. Riser 380,
as well as submount 390, are further coupled to a top surface of
the substrate 300. Riser 380 and submount 390 enable vertical
transmission line 540 to provide signal paths for RF interface 530.
The transmitter further includes optoelectronic component 510,
which can be any type of optoelectronic component, for example, a
laser diode.
To provide the optical transmission, the transmitter 500 further
includes an optical component 550 that transmits optical signals
using fiber/flexure 560. Conversely, the transmitter 500 is
converted into a receiver by utilizing a semiconductor detector as
the optoelectronic components and a transimpedance amplifier as
electrical IC 520.
Example System Applications
FIG. 8 illustrates one embodiment of an optical electronic system.
System 600 includes optical transmitter 610 which is, for example,
the transmitter described above having a vertical transmission
line. Optical transmitter 610 is coupled to printed circuit board
640 via lead frame 620. In one embodiment, optical package 610 is
configured as a transmitter, which includes semiconductor laser
630. Optical transmitter 610 communicates via semiconductor laser
630, while transmitting optical signals via optical cable 650. The
optical signals are received by optical receivers 660.
Optical package 660 is configured as an optical receiver, which
utilizes a lead frame 670 in order to form an electrical connection
to PCB 680. In order to receive optical signals, optical receiver
660 includes a semiconductor detector 662. The semiconductor
detector 662 receives an optical signal from optical cable 650 and
converts the optical signal into its original electrical signal
format. Signals can be transmitted within the receiver using a
vertical transmission line as described above.
Other applications include the use of these teachings in line cards
or a tranceiver/transponder, as well as other applications.
In one embodiment, the optical transmitter and the optical receiver
are components within an electronic system. FIG. 9 is a block
diagram of one embodiment of an electronic system. The electronic
system illustrated in FIG. 9 is intended to represent a range of
electronic systems, for example, computer systems, network access
devices, etc. Alternative systems, whether electronic or
non-electronic, can include more, fewer and/or different
components.
Electronic system 900 includes bus 901 or other communication
device to communicate information, and processor 902 coupled to bus
901 to process information. In one embodiment, one or more lines of
bus 901 are optical fibers that carry optical signals between
components of electronic system 900. One or more of the components
of electronic system 900 having optical transmission and/or optical
reception functionality can provide a vertical transmission line to
connect electronic circuitry to optical devices.
While electronic system 900 is illustrated with a single processor,
electronic system 900 can include multiple processors and/or
co-processors. Electronic system 900 further includes random access
memory (RAM) or other dynamic storage device 904 (referred to as
memory), coupled to bus 901 to store information and instructions
to be executed by processor 902. Memory 904 also can be used to
store temporary variables or other intermediate information during
execution of instructions by processor 902.
Electronic system 900 also includes read only memory (ROM) and/or
other static storage device 906 coupled to bus 901 to store static
information and instructions for processor 902. Data storage device
907 is coupled to bus 901 to store information and instructions.
Data storage device 907 such as a magnetic disk or optical disc and
corresponding drive can be coupled to electronic system 900.
Electronic system 900 can also be coupled via bus 901 to display
device 921, such as a cathode ray tube (CRT) or liquid crystal
display (LCD), to display information to a computer user.
Alphanumeric input device 922, including alphanumeric and other
keys, is typically coupled to bus 901 to communicate information
and command selections to processor 902. Another type of user input
device is cursor control 923, such as a mouse, a trackball, or
cursor direction keys to communicate direction information and
command selections to processor 902 and to control cursor movement
on display 921. Electronic system 900 further includes network
interface 930 to provide access to a network, such as a local area
network. In one embodiment, network interface 930 provides an
interface to an optical network by including an optical transmitter
having a vertical transmission line and/or an optical receiver
having a vertical transmission line as described in greater detail
above.
Instructions are provided to memory from a storage device, such as
magnetic disk, a read-only memory (ROM) integrated circuit, CD-ROM,
DVD, via a remote connection (e.g., over a network via network
interface 930) that is either wired or wireless providing access to
one or more electronically-accessible media, etc. In alternative
embodiments, hard-wired circuitry can be used in place of or in
combination with software instructions. Thus, execution of
sequences of instructions is not limited to any specific
combination of hardware circuitry and software instructions.
Reference in the specification to "one embodiment" or "an
embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment of the invention. The
appearances of the phrase "in one embodiment" in various places in
the specification are not necessarily all referring to the same
embodiment.
In the foregoing specification, the invention has been described
with reference to specific embodiments thereof. It will, however,
be evident that various modifications and changes can be made
thereto without departing from the broader spirit and scope of the
invention. The specification and drawings are, accordingly, to be
regarded in an illustrative rather than a restrictive sense.
* * * * *